Exposure timer



Nov my, 1923 1,474,342

7 W. C. ANDERSON Q smowrm. TIMER Filed April 1, 1922 2 Sheets-Sheet 1 Nov. 20, 1923 1,474,342

W. C. ANDERSON EXPOSURE TIMER Filed April 1. 1922 V asbestos-Sheet 2 1 Min 6 a Patented Nov. 20, 1923.

WILLIAM G. ANDERSON, or KANSAS pe-meson;

" n zrr'osn'nn rim-En;

A lication filed April 1,4922, Serial no; 5443565.,

To all whom it may concern:

Be it known that I, WILLIAM C. Annnnsom;

a citizen of the United States, residing at Kansas City, in the county of Jackson. and- State of Missouri, have invented certain new and useful Improvements in Exposure Timers; and I do declare the following to be a full, clear, invention, such and use the same, reference being had .toithe accompanying drawings, and to the letters and figures of reference marked thereon. which form a part of this specification.

This invention relates to exposurctimers and more particularly to a device forflcontrolling the lamps in a photograph printing machine whereby the timeof exposure may be made of long or short duration Modern studios are usually equipped with, printing machines for printing photographs;

rorn negatives but it is common practice for the operator to time the exposure by watch or his judgment, thus causing lac of uniformity in prints from the same negative and loss of time from mistakes.

It is therefore the principal object of the present invention to provide asimple yet.

durable mechanism which may be quickly and easily attached to any photograph printing machine whereby the pilot and printing lamps may be illuminated at the proper moment and during the proper interval of time. i

Another object of the invention is to provide a setting mechanism'whichmay be set for long or short exposures and which con trols a master switch in circuit with thepilot and printing lamps so that the lamps mav osition at which the setting mechanismlias een set, 1

In accomplishing these and other objectsof the invention I have provided the.im--

proved details of structure hereinafter described and illustrated in the accompanying drawings, in which: 1

Fig. 1, is a perspective view of a photo'- graph printing machine eguipped with: an exposure timer constructe in accordance with my invention. 7 I i and exact description of the as will enable others skilled in the art to which it appertains -to makek 6 and 7,,

be flashed on or off according .to-the gages the :pin 17 'n Fig p- 2,;is a perspectivegview ofth'e exposure timers Fig. 3,i

the case and-base being in vertical section to clearly illustrate the inter or mechan sm. Fig.';.&, .1s a

vertical section throu gt; the dial ken: on the line of Fig; 2."

1 g 5,: is a f ont, e o ii ida ts .beingbroken away for better. illustration,

;F1flf. ,6, 1S a similar view, takenvon the line 6-6 of Fig. 3. -Fig.- 7, is a plan sectional view entire line Fig. 8,, isLawirinigE' Referringmorein detail tothe ;1 d'esignates a base preferablyof castmav-terial, which supports 1 a front plate 2' and housing 3,- all ofwhich are fitted together to support and enclose.,the operating parts.

Pressed into a boss in the .front plate 2 is a shoulder stud. 4: which is held in position-by a setscrew 5-andwhich has for wardly and. rearwardly extending-portions .A knob ,8"-,is mounted so asrto turn freely on the portion (Sand is held thereon by a nut 9 and washer 10 in such a manner as to be engaged by a spring Washer 11 to pre vent the knob from becoming accidently moved after itis once set Theknob has a disk cr -cursor 1-2 secured to its rear 'face and provided with a finger 13 adapted to cooperate with the scale corresponding to seconds of time and numerals such as 510- l53, etc, showing thenumber-of seconds for which the device The disk, l2 carries a pin lt' which projects-through anareuate slot 16 in the front plate 2 and in the pathof a similar pin 17 projecting frornthe wormavheel 18, the

latter being ,fixed to-a hub revoluble on the portion 7 of the stud 4 and held in place by a nut 20 and washer 2i.

Surrounding the hub is a light coil spring .22, oneend ofwhich; engages a pin 9-3 in the other end of which en; the "worrn wheel so that theworm wheel willbe normally. returned frontplate and the to initial position withthepinlZ against s a side elevation riflthe timer,

14 preferably, cast; on the front plate 2 and composed of marks the pin 15, it being understood that the pin 15 may be in an one of the several positions depending on tlie position of the finger .13 with respect to the dial 14.

Pivotally mounted on a boss in the front plate 2 is the trunnion 24 of the arm 25 which carries the driving worm, trip and switch mechanisms presently described. The trunnion is held in place by a screw 26. the head of which seats against the outer face of the plate 2 so as to permit the arm to swing freely up or down.

Revolubly mounted in the arm 25 and at right angles to trunnion 24 is a shaft 27 which carries a worm 28 at one end and a belt wheel 29 at the other, the latter being connected by means of a belt 30 to the grooved pulley 31 on the motor 32 so that the motor will drive the worm 29. The motor is of the constant speed type and. the ratios of the belt wheels are such that the worm 29 will turn at a constant predetermined speed. i

The worm 28 lies immediately beneath the worm wheel 18 and normally out of mesh with it as shown in Fig. 5, but may be raised into driving relation therewith by mechanism consisting of a bell-crank lever 34 pivotally mounted on a boss on the front plate 2 and having one end adapted to engage the notched end of a latch lever 35 pivotally mounted on an extension 36 of the arm The lever 35 is held in upright po sition against a stop 37 by a spring 38 at-- tached to an upwardly inclined arm 39 of the latch 35 which lies in the path of the trip pin 17 of the worm wheel 18. (See Figs. 4 and 6.) The opposite end of the bell-crank lever 34 connects with a link 40 slidably mounted on the front plate 2 and projecting from the housing 3 so that a -cable may be attached thereto and to an ;operative part of the printing machine to =operate the timer as will be presently (,e

scribed. A spring 43 extends from the link to the front plate 2 so that the bell-crank is returned to normal position after each operation of the printer.

The extension 36 of the arm 25 also carries the central carbon 44 of an. automatic switch 45 which controls the white print ing lamps 46 and the red pilot lamp 47 of the printing machine.

The carbon 44 is held in a clamp 48 supported on an insulator 49 on the extreme end of the extension 36 and provided with a binding post 50. The switch also contains upper and lower carbon contacts 51 and 52 respectively which are slidably mounted in metal brackets 53 and 54 rigidly secured to an insulator 55 which is carried by the lug 56 on the front plate 2. The brackets 53 and 54 are provided with binding posts 57 and 58 for attaching the circuit wires and with spring pressed shoes 59 and 60 which bear against the ends of the carbons to hold them in functional position.

Each of the carbons 51 and 52 has a col-- lar 61 provided with a set screw 62 to clamp the collar to the carbon, and limit the movement of the carbon contacts in the brackets 53 and 54; it being understood that there is a slight vertical moven'ient of the upper and lower carbons when the central carbon engages them so as to permit of proper engagement or disengagement of the worm and worm wheel and insure a good contact in the switch.

The line wires 63 lead into a service connection 64 from which a wire 65 leads to a hand switch (36 having push buttons 67 and 68 for controlling the circuit. Another wire 69 leads from the hand switch 66 to the motor 32 and thence by a branch wire (39 to one side of the pilot lamp 47 and the bank of white printing lamps 46. A wire 70 connects the opposite side of the white printing lamps to the upper carbon 51 and a wire 71 leads from the opposite terminal of the pilot lamp 4'? to the lower carbon 52.

The central carbon 44 connects by a wire 72 direct to the service connection 64 but has a branch wire 73 which leads to the opposite terminal of the motor.

lVith the above described connection it is apparent that when the hand switch 56 is operated the motor will start and the red pilot lamp will be illuminated. because the motor is connected directly in the circuit and the central carbon 44 is resting on the lower carbon 52.

W'ith the parts in this position, the op crator can place a i'iegative on the glass panel 74 of the printing machine 75 and ar range sensitized paper in the proper p tion by the aid of the pilot lamp 47. A soon this is done. he lowers the platen To. against the paper and negative by means o l the printing arm 7'7 and in doing so. pulls the cable 73 which passes through an eye 7 on the machine and is attached to the link 40 of the timer so that the link is pulled outwardly from the housing when the print ing arm is lowered.

This action rocks the bell-crank lever 3-1- which engages the lever 35 and raises the arm 25, thus meshing the worm 23 with the worm wheel 13 and closing contact between carbons 44 and 51 and breaking contact between carbons 44 and 52. The red light therefore, goes out and the bank of white lights is illuminated so as to print the picture.

As the motor is constantly running the worm wheel 18 will move in the direction of the arrow (Fig. 6) during the printing operation and advance the. pin 17 from its position against the stop pin 15 to engagement with the arm 30 of the latch 35.rocking the latter as shown in dotted lines (Fig. 6)

and disengaging it from the bell-crank 34 therefore permitting the arm to fall by gravity disengage the worm from the worm wheel and break the upper contacts 44 and 51. The white lamps are thus extinguished at the proper time and the pilot lamp again is illuminated. r 7

It will be apparent that the time interval will be constant for each operation, but that the interval can be lengthened or shortened by moving the knob 8 so that the worm wheel 18 will have to move a greater or less distance before tripping the latch 35.

The case 3 is held in position by a pin 79 at the rear of the base and a screw 80 at the top of the front plate Q, so that the case may be easily removed to expose the parts for lubrication or repair.

It is to be understood that I have described and illustrated the preferred embodiment of my invention and that varia tions'may be made in both operation and structure without departing from the spirit and scope of the invention.

Having thus described my invention, what I claim as new therein and desire to secure by Letters-Patent is:

1. In an exposure timer, a circuit closer, an arm forming a part of said circuit closer and mounted for pivotal moveme a latch on said arm, albell-crank for engging said latch, a link for actuating said bell-crank, a worm in said arm, a rime mover for driving said worm. a worm wheel adapted for engagement with said worm at times, and

a trip pin on said Worm wheel for tripping said latch from said hclLcr-anlr tor the purpose set forth.

5).. in exposure timer comprising a frame, arm pivotally mounted in the frame. an insulated contact on said arm insulated contacts on said frame adapted for engagement by said arm contact a latch on said arm, a hell-crank on said frame adapted to engage the latch to raise the arm, a, link for actuating the hell-crank, a worm revolubly mounted in the arm, a motor for driving said worm at a constant e eed a worm wheel revoluhly mounted on sai frame and adapted for engagement with said worm. when said arm is. in raised position, a trip pin on said worm wheel for engaging said latch to release said arm, a dial, a cursor for said dial, a stop pin on said cursor in the path of said trip pin and a spring for moving! said trip pin againstsaid stop pin after i said arm is released.

3. An exposure timer comprising a frame, a circuit closer on said frame, an arm pivot ally mounted on said frame and adapted to actuate said circuit closer, a worm revolubly mounted in said am, a motor for driving said worm, a worm wheel revolubly mounted in said frame. a latch on said arm, manually operated mechanism for engaging Said latch to, raise said arm and mesh said worm and worm wheel. a trip pin in said worm wheel for releasing said latch, a dial, a cursor for said dial, a stop pin in said cursor in the path of said trip pin, a knob for manually moving said cursor and stop pin relative to said trip pin. a spring washer for frictionally holding said cursor in set position and a spring for moving said trip pin against said stop pin after the trip pin has released said latch and broken said worm and worm wheel connection.

4. In an exposure timer a circuit closer, upper and lower contacts for said circuit closer, a central contact adapted for engaging either upper or lower contacts, means for manually raising said central contact into engagement with said upper contact, motor driven mechanism for releasing said central contact to engage said lower contact and manually set timing mechanism for controlling the duration of contact between said central and upper contacts.

5. The combination with a photograph printing machine comprising a printing arm, of an exposure timer comprising a circuit closer, a link operable from said printing arm for functioning said circuit closer, motor driven mechanism for defunctioning said circuit closer and manually set timing mechanism for determining the functional period of said circuit closer.

6. The combination with a photograph printing machine comprising a printing arm, a bank of printing lamps and a pilot lamp, of a circuit closer comprising upper, lower and central contacts, a service connection having a wire connectedwith the central contact of the circuit closer and with the motor, a hand switch a second wire leadir from the service connection to the hand switch, a wire leading from the hand switch to the motor and pilot and printing lamps a wire leading from the pilot lamp to the lower contact of the circuit closer, wire leading from the printing lamps tn the 'upper contact of the circuit closer, means connecting the printing arm with the central contact of the circuit closer to switch said printing lamps intc circuit when said print-- ing arm is lowered and means for automatically releasing the central contact ofthc circuit closer to disconnect said printing lamps and connect said pilot lamp into the circuit.

'7. An exposure timer comprising a front plate having an arcuate slot, a graduated dial concentric with said slot, a cursor revoluble over said dial, means for frictionally holding said cursor, stop pin on said cursor projecting through said slot, a worm wheel concentric with said cursor. a trip pin on said worm wheel normally lying against said stop pin, a circuit closer, means for actuating said circuit lliii wheei T301" returning said trip pin 531d. smp p111.

ili-iestiimmy wvhcrvof I hereby nfiix my s-ngnutm-o m presenceof two wltxmsses.

NV. G. ANDERS N Witnesses: V

A. L. (JO STOCK, JOHN N. SI'RINK, Jr. 1 

